Camper trailer wiring.


  #1  
Old 06-18-22, 09:30 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
Camper trailer wiring.

Hey everyone, I got a camping trailer today and am excited to restore it!

I am trying to figure out the wiring on it.

It has an extension cord that plugs into a house outlet.
Plugging the extension cord in gives me power to a 115V plug inside the trailer.
Nothing else has power.

There is also a 7 pin wire harness on the trailer and my truck has a 7 pin connector but nothing happens when I plug it into my truck.
There is no area or signs that the trailer requires a battery.

The trailer has these following circuits.
5 total interior lights
Water pump
Heater
A knob that spins near the door entrance that has 2 wires attached to it.


There is 3 fuses:
Water pump
Lights
Heater

All fuses are good, I don’t see any breaks or cuts in the wires.

There is a switch for the water pump
ON-OFF

There is a switch labeled “Truck battery”
ON-OFF


One interior light was working when hooked up to the extension cord, then I tried turning another light on and off a few times and the working light stopped working.

I have no idea how this is supposed to work.

I may delete the heater and the only things that would be left that need power would be interior lights and water pump.

Before I put 2 batteries in the trailer and run my own wires, can someone explain how this works or what may be wrong?
Nothing is getter power. I wired up the water pump to my car and it worked, so I’m assuming everything works, just has no power.

Thanks.





 
  #2  
Old 06-19-22, 12:43 PM
badeyeben's Avatar
Member
Join Date: Dec 2006
Location: Southern ILLINOIS
Posts: 1,187
Received 59 Upvotes on 53 Posts
Sounds to me like the camper is wired for 12 volt dc only. It looks like the thing you show with the plug in is an inverter that changes the ac voltage to dc voltage. If you turn on the switch marked truck with the 7 pin plug attached you should be able to run the pump and lights. That is if the 7 pin plug is wired correctly. Then it would be running off the truck battery.
Seems to me the old camper I had was that way Everything but the heater ran off 12 volt dc voltage. Plugging in to the power from outside turned the inverter on so the 12 volt dc power came from there instead of the truck battery.
Any time the switch is on the truck battery is being used. So be sure to turn it off when using outside power so it does not go dead and not be able to start the truck.
 
  #3  
Old 06-19-22, 12:47 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,816
Received 3,922 Upvotes on 3,518 Posts
There are a lot of things going on there.
A lot of handyman work that will take time to locate and understand.

Typically the always live connection to the 7 pin plug is not live by default.
Neither is the brake line.
At the very least it will require a fuse in the fuseholder.
Refer to the owners manual on towing setup.
 
  #4  
Old 06-19-22, 05:06 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks to both of you.

the truck has tow package and tow module installed, but I’m not sure if there is a fuse for the 7pin 12v lead. I will have to look at it.

I called an rv repairman and he said the inverter is bad. Is it possible to add 12v batteries to the current trailers wiring?

I would like to have some power with the truck off and the trailer not plugged into power.

The system does look a bit messy with no real diagram available.

I’ve been reading and watching videos about some wiring diagrams.

it looks like this is the way they are generally wired.

12v battery.
+ go fuse box
- to trailer frame
7 pin 12v + to + battery
7 pin 12v ground to trailer frame
This charges the trailers battery?

Then from the trailers fuse box:
+ Wires ran to different accessories
Interior lights
Exterior lights
Water pump
Etc etc.

All ground wires from accessories are grounded to the trailer frame.
Add switches between accessory ground and trailer frame for On/Off function.

Does this sound right?
The only thing I have not Figured out to add is the Dc to Ac converter.

From what I’ve seen, the inverters have 2 prongs that allow +/- from the battery to
be plugged into….?

 
  #5  
Old 06-21-22, 07:55 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
Can you confirm my Camper wiring diagram?

Can someone please look at this diagram and see if I am missing anything or if something looks incorrect.

The current 7 pin harness is crumbling due to age and there’s a mess of wires that I have no clue what they belong to and there doesn’t seem to be any accessory that they belong to.
The only wires I will be keeping are the ones that run up to the ceiling lights. To avoid running wires through the walls.


Heres the rundown of how I plan to wire the camper and the 7 pin wire harness.

From the 7 pin harness
running lights to lights
reverse lights to lights
left turn signal to light
right turn signal to light
electric brakes
12v wire to 2 12v batteries wired in parallel
Ground wire to 2 12v batteries

Battery diagram
12v battery terminal to fuse box
Battery ground to ground block
12v battery to AC to DC converter
Battery ground to AC to DC converter

Fuse box will house fuses for the trailer
Interior lights
Exterior lights
Water pump
Random accessories

Ground block will be grounded to the trailer frame as well as send ground to accessories

I will install a kill switch between the 12V battery terminal that is going to the fuse box. This way, I can cut all power when it’s not in use.
The kill switch is missing in the diagram.

My main question is, does this look correct?

Second question, since the ground block will be grounded to the trailer frame, can I attach any accessory grounds to the frame too? This would be to avoid excess wires to any add on accessories.

Im the diagram, I have switches for the lights and pump on the negative side to complete the circuit.
is this fine? Or should the switches be on the + side?

The AC to DC converter is designed to run all 12v accessories and charge my batteries when not hooked up to a truck and plugged into shore power yes?

The camper currently has a “Truck battery” On/Off switch. I don’t know how that is wired in. Do I need to add one of those switches?

The 7 pin harnesses I’ve seen have a a block with all 7 wires. This seems useless. I can just run the 7 wires to the trailer lights and the batteries right?

Thanks.

 

Last edited by XSleeper; 06-21-22 at 09:41 PM.
  #6  
Old 06-22-22, 01:22 AM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
According to a video I saw, I was very wrong.

I have re made the wiring diagram.
The video shows a breaker box going to shore power and then the converter going to the breaker box. I see no need to the breaker box if I will not have 110v outlets on board.

Here’s the diagram typed out.

Converter box:
+12v to to 12v fuse box
Ground to ground bus bar

2 batteries wired in parallel:
Ground to ground bus bar
12v+ to fuse box with a kill switch to shut off all power to trailer when not in use
12v+ in line Reseting breaker

Fuse box:
Interior lights
Exterior lights
Water pump
Misc. items-Radio? Vent fan? Ice cooler?

Ground bus bar:
Interior lights
Exterior lights
Water pump
Misc. items

7 pin connector on the truck:
12+ auxiliary to fuse box
Ground to ground bus bar
5 other wires for each of the lights.


Some concerns,
Looks good?
The video I saw used breakers in a breaker box.
The converter box I am looking at only has 2 small fuses on it. Is this ok?
The Ground wire from the 7 pin was said to go to the ground bus bar for charging the batteries, how will the trailer lights ground and function?
There is no chassis/frame ground, do I add one? If so from where?




 
  #7  
Old 06-22-22, 07:48 AM
A
Member
Join Date: Aug 2015
Location: USA
Posts: 1,047
Upvotes: 0
Received 112 Upvotes on 97 Posts
suspect you will need a chassis ground for the lights easiest place would probably be near the tongue or trailer connector where you have easy access to the chassis frame to install a connector eyelet but suppose you could do it anywhere distribution block or buss bar may not be as easy to connect to chassis.
switches can be placed on pos or neg side of the circuit does not matter.
 
  #8  
Old 06-22-22, 08:43 AM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks for the reply.

I asked on Facebook and people are insistent I add a breaker box.
I don’t see why I need one if I don’t need 110v outlets. The video I saw plugs the breaker box into shore power and the converter into the breaker box. The way I see it, the breaker box is just a middle man.

I could add a ground near the front of the trailer. But which wire is grounded? The negative wire from the 7 pin harness?
Does the battery have to be grounded to the frame too?

Thanks.
 
  #9  
Old 06-22-22, 06:20 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
I’ve added a breaker box to my diagram.
I think it looks good to go but still need confirmation.

 
  #10  
Old 06-22-22, 10:22 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,816
Received 3,922 Upvotes on 3,518 Posts
You don't need a breaker box for a single receptacle.
. You could have a receptacle that is fed directly from a rubber cable and plug.

Your trailer should be standalone. When you are using it the connection to the truck system (aux) power should be opened. You should only be using the towing vehicle to charge the camper batteries. If you leave everything connected at all times you run the risk of discharging the truck battery.

 
  #11  
Old 06-23-22, 12:39 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
How do I run a single cord to 1 receptacle?
Plug 1 end of the cord into the receptacle and the other end into shore power?
I still need to be able to plug my converter into shore power too so I can charge the batteries.

I just need 1 receptacle for maybe a microwave during the day and a rv or maybe a small ac unit at night.
Everything else will run off 12v or propane.

Yes, I had planned to only have the 7 pin trailer harness connected up to the truck when driving.
1 reason for charging and 2nd reason for trailer lights.

Then disconnect the trailer harness from the truck when parked.
 
  #12  
Old 06-23-22, 02:57 PM
A
Member
Join Date: Aug 2015
Location: USA
Posts: 1,047
Upvotes: 0
Received 112 Upvotes on 97 Posts
if you're going to have outlets and power appliances then you likely want a breaker box.
you also might want a power distribution block similar to a bus bar but insulated from ground allowing you to run all positive power wires to a central point, converter +, each battery +, trailer plug aux + , then you would run a wire from distribution block to fuse block if you want a kill switch and still be able to charge your batteries on shore power you would likely want the switch between the power distribution block and fuse block.
 
  #13  
Old 06-23-22, 09:21 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
I’ve made probably the 10th revision and I think (again) that it’s ready and correct.

I added the kill switch between the circuit breaker and the fuse box so I can cut all power to the trailer while driving but still charge my batteries.

The inline fuse on the 12v 7 pin connector is to make it easier to replace, rather than look through my trucks fuse box.

I also added the inside wiring of the breaker box.

How’s it look?

Thanks.

 

Last edited by Serf27; 06-23-22 at 11:57 PM.
  #14  
Old 06-24-22, 10:31 AM
A
Member
Join Date: Aug 2015
Location: USA
Posts: 1,047
Upvotes: 0
Received 112 Upvotes on 97 Posts
would look at the circuit protection on the vehicle and see where it is just adding an additional fuse does not really mean that's the one that will blow, would look under the hood around the battery and under hood fuse block distribution block as likely spots aux or brake may have been added if it had factory options it is likely in the under-hood fuse block.
your converter is a multi-stage battery charger, so I am not seeing why you wouldn't connect it to the batteries directly you still have the switch in between it and the batteries. just one scenario you're not using the trailer but plan to one weekend and want to make sure the batteries are charged you plug in the converter and charge the batteries no reason to have to turn on the fuse block switch as you're not actually using the trailer but plan to on the weekend all you want to do is charge batteries.
One last thing you may keep in mind is based on location of the converter, fuse box in relation to batteries the closer to the batteries you can get these items may reduce the amount of larger gauge wiring you would have to run really depends on the trailer and what space you have available.


 
  #15  
Old 06-24-22, 11:04 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,816
Received 3,922 Upvotes on 3,518 Posts
Most vehicles have a 30A fuse in the underhood fusebox for the AUX power on the always live line. To help prevent that from blowing.... you could use a 25A fuse in the camper.

In any event.... carry spares.
 
  #16  
Old 06-24-22, 11:43 AM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
There are 2 fuse boxes in the truck.
One is in the hatch and way to get to.
the other one is under the dash and a real paint to get to.
I figure 1 fuse in the truck sends power to the 12v on the 7 pin.
And if I add a fuse on the 12V 7 pin wire, that fuse will blow before the fuse on the truck blows. That way I don’t have to look through 50 or so fuses in the truck.
That makes sense right?
PJmax, I added a 30amp fuse to my diagram on the 12v 7 pin wire.
I will carry spare fuses. I’m trying to figure everything out before sending power so nothing has a chance to go wrong.

Alan, you are right, I could wire the converter right to the batteries, since they will be joined on the fuse block because they will most likely be on the same stud.

But if for whatever reason I have no batteries, the converter could still power the trailer with shore power if the converter + is on the fuse box.


I have been debating on where to place everything.
I have no battery box or J-Box everything will have to be made.
I was planning on having the battery box and J-Box in the front of the trailer and running the +/- wires inside to the fuse box.
I wouldn’t have to go outside if a fuse goes out.

If I need thicker gauge wires, then I’ll just make a big box in front of the trailer to house everything.

That was going to be my next question, wire gauge.
What gauges could you all recommend?
I’m sure the 12v accessories can all be the same gauge.
Interior lights, exterior lights, water pump, radio, etc.

I was thinking 10 gauge wire from battery -/+ to J-box/fuse box and 10gauge wire from the converter to +/-.

4 gauge wire for battery to frame ground
4 gauge wire for battery parallel wiring.
 
  #17  
Old 06-24-22, 12:38 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,816
Received 3,922 Upvotes on 3,518 Posts
You can use #18 or #16 for the lights...... #16 for heavy devices like a pump.

I added a 30amp fuse to my diagram on the 12v 7 pin wire.
That's fine but in that case the under hood fuse could open first.
 
  #18  
Old 06-24-22, 12:47 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
The lights will be led.

10 gauge wire is ok for any battery and converter wires?

If the truck fuse blows first, it would only do so because there is a fault in the truck right, not the trailer?
 
  #19  
Old 06-24-22, 02:42 PM
A
Member
Join Date: Aug 2015
Location: USA
Posts: 1,047
Upvotes: 0
Received 112 Upvotes on 97 Posts
see 6 gauge recommended for up to 45 amps and 15 feet in length but there is many wire gauge charts online ultimately there not all the same, you likely will not be using that much for lights and water pump and acc but where you converter will likely put out a lot of amps is charging the batteries. looks like powermax recomends minumum of 8 gauge.
should not need 4 gauge cables at batteries either if there only going to see 45 amps no reason to really go larger than 6 gauge but if you ever add a 120 inverter or something that may require a lot of amps guess you could just install larger cables then.
not really seeing no battery being an issue assuming the positive battery connections are not grounded and the converter is ok with no battery.


 
  #20  
Old 06-24-22, 03:29 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
I think I am going to put all of this in the front of the trailer. I will build a wooden box that will house the batteries, converter, fuse, J-box and breaker box.

So I think any cables from the battery or converter will only run about 2-3ft.
Should I still opt for 6gauge battery wire?

The only wires that will travel more than 3 ft will be the breaker box to outlet wires and breaker box to shore power wire and any 12v accessory wires.
the trailer lights will be ran under the trailer against the frame.

No 110v outlets will work when I’m on battery power right?
That’s what an inverter is used for right?
 
  #21  
Old 06-24-22, 04:27 PM
A
Member
Join Date: Aug 2015
Location: USA
Posts: 1,047
Upvotes: 0
Received 112 Upvotes on 97 Posts
would probably be fine using the manufacturers minimum of 8 gauge given the short lengths of wire.
from the fuse block you can use smaller wire lights likely only draw a few amps so 16 gauge is likely fine pump seeing some as high as 15 amps but many are likely much lower than that still may want 10 gauge for pump and acc mainly cause if you add a power outlet you never know what you may plug into it air compressor or something like that could potentially have high amp draw.
your 110 volt outlets would not work without an inverter just off the batteries.
 
  #22  
Old 06-26-22, 09:57 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks Alan, I will run 10 gauge to the water pump.
the interior lights look to be 16 gauge and have 5 lights wired into 2 wires.
I am hoping these wires are enough to run the 5 interior lights because it looks like I’d have to remove any panels in the way to route new, thicker wire.

I may look into installing an inverter later on.
 
  #23  
Old 08-22-22, 05:00 PM
S
Member
Thread Starter
Join Date: May 2015
Location: USA
Posts: 51
Upvotes: 0
Received 0 Upvotes on 0 Posts
Almost 2 months since I asked this, wow!

I’m nearing the interior work and time to start hooking up wires to switches and accessories.

Current 12v accessories include:
Cargo lights
Exterior porch lights
Water pump.

I’ve ordered this switch panel.
Limited-time deal: Nilight 90101E 5Gang Multi-Function 5 Gang Rocker Dual USB Charger + Digital Volmeter +12V Outlet Pre-Wired Switch Panel with Circuit Breakers for RV Car Boat Truck Trailer,2 Years Warranty https://a.co/d/44YSmEO

I have a similar one in my boat and it works great, but there’s not much stuff on the boat that pulls power, so it works great.

I’m sure the switch panel in the trailer is capable of operating the led lights.

Can it handle the water pump though?
I would be running a 10 gauge 12V power wire from the + Junction box to the switch panel + wire and then the switches on the switch panel would all have power.

Any issues with this with the water pump being on along with other 12V accessories?

The water pump I’ve ordered has a current draw of 5 Amps and the switch panel shows a current draw of 15 Amps.

Thanks.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: